Docosahexaenoic acid (DHA) is one of the most important omega-3 fatty acids.
Like most omega-3 fats, it’s linked to many health benefits.
Part of every cell in your body, DHA plays a vital role in your brain and is absolutely crucial during pregnancy and infancy.
Since your body can’t produce it in adequate amounts, you need to obtain it from your diet.
This article explains everything you need to know about DHA.
DHA is mainly found in seafood, such as fish, shellfish, and fish oils. It also occurs in some types of algae.
While it can be synthesized from alpha-linolenic acid (ALA), another plant-based omega-3 fatty acid, this process is very inefficient. Only 0.1–0.5% of ALA is converted into DHA in your body (
Because your body can’t make DHA in significant amounts, you need to get it from your diet or take supplements.
DHA is vital for your skin, eyes, and brain. Your body can’t produce it in adequate amounts, so you need to obtain it from your diet.
Therefore, adequate levels of DHA seem to make it easier, quicker, and more efficient for your nerve cells to communicate.
Having low levels in your brain or eyes may slow the signaling between cells, resulting in poor eyesight or altered brain function.
DHA makes the membranes and gaps between nerve cells more fluid, making it easier for cells to communicate.
DHA is mainly found in seafood, such as fish, shellfish, and algae.
Some fish oils, such as cod liver oil, can provide as much as 1 gram of DHA in a single tablespoon (15 ml) (17).
Just keep in mind that some fish oils may also be high in vitamin A, which can be harmful in large amounts.
What’s more, DHA may occur in small amounts in meat and dairy from grass-fed animals, as well as omega-3-enriched or pastured eggs.
However, it may be hard to get enough from your diet alone. If you don’t regularly eat these foods, taking a supplement may be a good idea.
DHA is mostly found in fatty fish, shellfish, fish oils, and algae. Grass-fed meat, dairy, and omega-3-enriched eggs may also contain small amounts.
DHA is the most abundant omega-3 in your brain and plays a critical role in its development and function.
Plays a major role in brain development
DHA intake during the third trimester of pregnancy determines the baby’s levels, with the greatest accumulation occurring in the brain during the first few months of life (
These parts of the brain are responsible for processing information, memories, and emotions. They are also important for sustained attention, planning, problem solving, and social, emotional, and behavioral development (
In animals, decreased DHA in a developing brain leads to a reduced amount of new nerve cells and altered nerve function. It also impairs learning and eyesight (
May have benefits for the aging brain
Interestingly, many of these changes are also seen when DHA levels decrease.
Low levels are linked to brain diseases
Alzheimer’s disease is the most common form of dementia in older adults.
Reduced episodic memory is among the earliest signs of brain changes in older adults. Poor episodic memory is associated with difficulties recalling events that occurred at a specific time and place (
Studies show that higher blood DHA levels are linked to a reduced risk of dementia and Alzheimer’s (
DHA is essential for brain and eye development. As such, low levels may disrupt brain function and are linked to an increased risk of memory complaints, dementia, and Alzheimer’s disease.
DHA helps activate rhodopsin, a membrane protein in the rods of your eyes.
DHA is important for vision and various functions inside your eye. A deficiency may cause vision problems in children.
Omega-3 fatty acids are generally linked to a reduced risk of heart disease.
This applies especially to the long-chain omega-3 fatty acids found in fatty fish and fish oils, such as EPA and DHA.
Their intake can improve many risk factors for heart disease, including:
- Blood triglycerides. Long-chain omega-3 fatty acids may reduce blood triglycerides by up to 30% (
65, 66, 67, 68, 69).
- Blood pressure. The omega-3 fatty acids in fish oils and fatty fish may reduce blood pressure in people with high levels (
70, 71, 72).
- Cholesterol levels. Fish oils and omega-3s may lower total cholesterol and increase HDL (good) cholesterol in people with high levels (
73, 74, 75).
- Endothelial function. DHA may protect against endothelial dysfunction, which is a leading driver of heart disease (
76, 77, 78, 79).
While some studies are promising, many don’t report any significant effects.
DHA may reduce your risk of heart disease by lowering blood triglycerides and blood pressure, among other effects. However, its role in heart disease prevention is controversial.
DHA may also protect against other diseases, including:
- Arthritis. This omega-3 reduces inflammation in your body and may alleviate pain and inflammation related to arthritis (
- Cancer. DHA may make it more difficult for cancer cells to survive (
82, 84, 85, 86, 87).
- Asthma. It may reduce asthma symptoms, possibly by blocking mucus secretion and reducing blood pressure (
88, 89, 90).
DHA may relieve conditions like arthritis and asthma, as well as prevent the growth of cancer cells.
DHA is critical during the last months of pregnancy and early in a baby’s life.
Deficiency is associated with changes in brain function, including learning disabilities, alterations in gene expression, and impaired vision (
During pregnancy and early life, DHA is vital for the formation of structures in the brain and eyes.
Children up to the age of 2 may need 4.5–5.5 mg per pound of body weight (10–12 mg/kg), while older children may need up to 250 mg per day (104).
Interestingly, curcumin, the active compound in turmeric, may enhance your body’s DHA absorption. It’s linked to many health benefits, and animal studies suggest that it may boost DHA levels in the brain (
Therefore, curcumin may be helpful when supplementing with DHA.
Adults should get 250–500 mg of combined EPA and DHA daily, while children should get 4.5–5.5 mg per pound of body weight (10–12 mg/kg).
DHA supplements are usually well tolerated, even in large doses.
However, omega-3s are generally anti-inflammatory and may thin your blood. Consequently, too much omega-3 may cause blood thinning or excessive bleeding (
If you are planning surgery, you should stop supplementing with omega-3 fatty acids a week or two beforehand.
Additionally, consult with your healthcare practitioner before taking omega-3s if you have a blood clotting disorder or take blood thinners.
Like other omega-3 fatty acids, DHA may cause blood thinning. You should avoid taking omega-3 supplements 1–2 weeks before surgery.
DHA is a vital component of every cell in your body.
It’s essential for brain development and function, as it may affect the speed and quality of communication between nerve cells.
Furthermore, DHA is important for your eyes and may reduce many risk factors for heart disease.
If you suspect you’re not getting enough in your diet, consider taking an omega-3 supplement.